SubSeven is a Backdoor program (as for example NetBus, Back Orifice etc.), which allows a third party to have access to a system. The program consists in a Server- and a Client program, which enable remote access to network computers, i.e. using the Client, a hacker can penetrate an infected system with the Server (this is the actual Trojan).

SubSeven Version 1.7 will first deliver an "Editserver", which makes the removal more difficult, because the attacker can easily modify the Server.